Lithium tri-tert-butoxyaluminohydride → Methyl 3-acetyloxy-12-hydroxydeoxycholan-24-ate

Participants

Reaction Steps

A THF solution of lithium tri-tert-butoxyaluminum hydride (1 M, 22.4 mL, 22.4 mmol) was added drop wise to a solution of compound 2.0a (2.5 g, 5.6 mmol) in THF (25 mL) at ambient temperature. After stirring for an additional 4-5 h, the reaction was determined to be complete by TLC. The reaction was quenched by adding aqueous HCl (1 M, 10 mL) and the mixture was diluted with EtOAc (30 mL). The phases were separated and the organic phase was washed sequentially with water (15 mL) and saturated brine solution (10 mL). The organic phase was then dried over anhydrous Na2SO4 (3 g) and filtered. The filtrate was concentrated under vacuum and the resulting solid was purified by column chromatography [29 mm (W)×500 mm (L), 60-120 mesh silica, 50 g], eluting with EtOAc/hexane (2:8) [5 mL fractions, monitored by TLC with p-anisaldehyde charring]. The fractions containing the product were combined and concentrated under vacuum to provide compound 2.1a (2.3 g, 91%) as a white solid.

Provenance & Evidence